Hardware Interfaces
FOX3-2G/3G/4G Series Hardware Manual
34
7.2.2.
1-Wire interface description
A 1-Wire bus uses only one wire for signaling and power. One or several 1-Wire devices can be
connected to the bus at the same time. Only one master should be connected to the bus.
Driver identification, temperature and humidity sensors are quite often used on vehicle applications.
Thanks to the integration of 1-wire interface into the FOX3-2G/3G/4G devices, the system
integrators for telematics, fleet management and intelligent transportation system can be cost-
benefit and time efficiently for their work due to the use of extra external devices which are not
integrated in the in-vehicle computers. Using of the 1-Wire interface, you are able to know which
drivers are in which vehicles and at the same time monitor the temperature and humidity of their
refrigerated trucks. In this way, shippers can record by their server the transportation and the
delivery state of their temperature-sensitive loads.
How does it work?
A 1-Wire network consists of a master controller which is connected to one or many slave devices.
The 1-Wire interface on FOX3-2G/3G/4G is a master controller. All of the actual monitoring
devices (lightning detector, moisture meter, motion detector, barometer, etc.) are slave devices.
FOX3-2G/3G/4G communicate with temperature and iButton devices via 1-Wire protocol
developed by Dallas Semiconductor, sending and receiving signals over a single data line plus
ground reference. The 1-Wire protocol synchronizes the monitoring devices to the FOX3-
2G/3G/4G. FOX3-2G/3G/4G initiate and requests all activities on the 1-Wire network. One key
feature of the Dallas system is that every 1-Wire slave device has a guaranteed unique address
saved on-chip ROM (Read Only Memory). This enables the master to recognize individually each
of your slave devices, and means you can have multiple devices of the same type on the same
network without conflict.
Figure 13:
Typical application connection
Setting up a 1-Wire network with the FOX3-2G/3G/4G devices is quite easy. 1-Wire is a simple
system of devices such as temperature, iButton devices etc. that are connected through the 1-
Wire data line plus ground reference to the FOX3-2G/3G/4G devices. Remember that you can
use and connect to the FOX3-2G/3G/4G 1-Wire line only sensors that require power supply
anywhere between 2.9V and 5.0V. FOX3-2G/3G/4G devices receive on demand the unique
address of the temperature and iButton IDs and other information they deliver. This information
can then be sent via alarms to the remote TCP server.
Figure 13.1:
Typical application using 1-Wire single line.
More details about the 1-Wire interface, refer to the application note
"AppNote_1-Wire_Guide.pdf"
.
